1. Field of the Invention
This is a continuation-in-part of application Ser. No. 09/516,551, filed Mar. 1, 2000, now abandoned. The invention relates primarily to sign displays in stores. More particularly, the present invention concerns releasable twist lock fasteners for securing displays to a suspended ceiling.
2. Description of Related Art
Clip assemblies for hanging objects from suspended ceiling grid work are known in the art. U.S. Pat. No. 4,323,215 to Berger, discloses one known hang-up fixture. The fixture includes a flat seating surface with spaced apart upward projections each having a laterally directed fin. When installed, the fins and the flat seating surface act as clips and hold onto a horizontal flange of an inverted T type grid work member. The fixture can be installed by using an extension pole with an installation tool mounted on its distal end. In at least some installations, the amount of friction applied between the clips of the fixture and the grid work member is insufficient. Small torques, inadvertently applied by installers, or even by a breeze acting on a sign being carried by the fixture, can be enough to dislodge the fixture and send the sign crashing to the ground.
U.S. Pat. No. 4,191,352 to Schuplin discloses a known rotatably installed suspension clip that addresses the insufficient friction issue. The disclosed clip is made of sheet metal. Bent arm portions of this clip are similar to the fins of the Berger fixture. A section of the bent arm portions is partially severed, bent downward and formed into a pointed barb. Any inadvertently applied dislodging torque, forces the barb to bite into the grid work flange and bind, thus preventing the suspension clip from being easily dislodged. In order to intentionally remove the clip, the barbs must be individually pried and bent upward with a screwdriver or the like. This is a slow, time consuming task, and often requires maintenance personnel to work from inconvenient and precarious ladders. Additionally, the barbs can scratch and mar the paint or protective coating of the grid work. In this regard the suspension clip of Schluplin is not releasable. As used here releasable means easily removable, without the used of tools such as screw drivers or pliers for prying parts of the sign hanger out of engagement with the associated ceiling grid or other hanger support. (obviously, reach extending tools operative to facilitate the installation or deinstallation such as those described below are not for prying parts of the sign hanger out of engagement with the associated ceiling grid hanger.)
In addition to the problems outlined above, both of the known clips previously mentioned are also limited in the size and weight of the object that can be carried.
U.S. Pat. No. 4,564,165 to Grant et al. shows a two-piece attaching device that most likely requires the use of a ladder to install. Its use is limited to hanging signs that can have their upper edge bent into an inverted V-shaped lip. The lip is then used to beneficially apply the weight of the sign to portions of the attaching device in such a way as to press shoulders of one part of the device into pockets of another part of the device. An attempt to hang some other sort of item from the attaching device, such as, for example, a plant, would likely result in unbalanced forces being applied to portions of the attaching device, resulting in the shoulders becoming disengaged from the pockets and the plant and at least one part of the attaching device falling to the floor.
Conventional clips or hangers have a number of disadvantages. Some of them can become disengaged too easily. Others bind and bite into the flange they are installed on, are difficult to remove, and are not releasable as the term is used here. Still others are comprised of multiple components and are adapted for use with only one type of object. Also, none of the prior art designs can support wide banners from a single one-piece clip.
Accordingly, it has been considered desirable to develop a new and improved ceiling grid sign hanger construction, which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.